One night last spring, I burst out bawling over the money my husband and I had lost in the stock market many months earlier—and then just as suddenly, my mourning morphed into rage, as I unleashed a litany of recriminations toward him that kept us up late into the night. I felt utterly distraught about our marriage, and life in general. The next morning, on day 25 of my menstrual cycle—4 days early—I got my period. It wasn't the first cycle that had been short or the first time my anger had reached a frenzied pitch in recent months, though I hadn't equated it with my period nor my age. Until now. It dawned on me that perhaps, at 47, I was experiencing something I knew very little about—perimenopause.

I apologized to my husband and set out on a journey to figure out what was happening to me—and about 40 million other midlife American women. As I queried my friends and their friends, I quickly realized that many of us are willfully in the dark about perimenopause (we all feel too young for this milestone). Every friend had questions—most commonly "How do I know I'm in it?"—and each woman, it seemed, was experiencing something slightly different from the next.

Before I dug into the research, I assumed that it meant a wave of weird periods before the real hot-flashy menopause hit. Not true. In perimenopause, which usually begins in your 40s (but can start as early as the late 30s), you can suffer depression and anxiety, relationship-threatening rage, embarrassingly heavy periods, life-interrupting hot flashes, insomnia, exhaustion, tip-of-the-tongue forgetfulness, migraines, and the list goes on ad nauseam (and that too!).

The kicker is, you may be experiencing one or several of these symptoms long before you and your doctor realize it. What's reassuring: Shifting hormones don't make you any less healthy, says Nanette Santoro, MD, director of the division of reproductive medicine at Montefiore Medical Center/Albert Einstein College of Medicine. And there's a lot you can do—from diet and lifestyle changes to medications—to reduce your symptoms dramatically. Here, a guide to recognizing the signs (heads out of the sand, please!). Then, how to successfully navigate this next phase of life with your health and happiness intact.

What the heck is perimenopause?

It's the transition stage in a woman's reproductive life that begins, on average, 4 to 5 years before menopause. During that time, your ovaries gradually produce less estrogen, causing follicle-stimulating hormones (FSH)—which are responsible for growing and developing eggs—to rise and menstrual cycles to shorten. Eventually, you begin to miss periods. Then estrogen plummets, FSH levels remain high, and ovulation (and finally menstruation) stops. When you've gone 12 months without a period, menopause officially begins.

It progresses at a different pace for everyone and not always in a straight line. One indicator that menopause is close: You don't get your period for more than 3 months, says Michelle Warren, MD, medical director of the Center for Menopause, Hormonal Disorders, and Women's Health at Columbia University Medical Center. "That means you'll likely stop having periods within a year." Symptoms tend to intensify as menopause gets closer, and you can expect them to be at their worst 1 to 2 years both before and after menopause, says Joann Pinkerton, MD, medical director of the Midlife Health Center at the University of Virginia. That's because estrogen decline accelerates closer to menopause, and many symptoms are related to withdrawal from the hormone. With time, though, most women adapt to the loss of estrogen, and symptoms ease.

Six key symptoms

Neither research nor experts can say which symptoms you'll experience and whether they'll continue from month to month. "One of the hallmarks of perimenopause is its unpredictability," says Pinkerton. That's why experts don't recommend testing your levels of FSH to determine if you're perimenopausal. Wildly fluctuating hormones often mean that the test cannot accurately predict where you are in menopause. Instead, pay attention to your cycle length and symptoms. Here, some of the most common.

Hot flashes. Though scientists don't know the exact cause, they suspect a drop in estrogen may disrupt your body's thermostat, resulting in a hot flash. About 75 to 80% of women experience hot flashes, which can last from a few seconds to 10 minutes and be as mild as a flushed face or so intense as to cause perspiration and heart palpitations. If you smoke, are overweight, or are African American, your risk of getting them increases. Hot flashes accompanied by sweating can also occur after-hours—these are called night sweats and may interfere with your quality of sleep.

Mood swings. The anger jags I experienced are what experts believe to be the earliest signs of, and they can begin even before your cycle shortens. Nearly 40% of women have mood swings associated with hormonal changes—from feelings of rage to intense PMS moodiness, anxiety, or despair, says Warren. One study found that the risk of depression doubles when women enter perimenopause; and if you've suffered from PMS or postpartum depression, you may be even more prone.

Irregular periods. As ovulation becomes more erratic, your cycle may shorten by a day or two and then by several days, and your flow may go from light to superheavy and clumpy; you may also experience severe cramping. When you don't ovulate, the endometrium, which sheds during menstruation, tends to overgrow, causing the excessive blood. Eventually, you'll have fewer and fewer periods, though they may still be heavy.

Low libido. Sexual desire may change, but studies show that for many women, a good sex drive before perimenopause will continue after.

Vaginal dryness. Low estrogen levels cause the tissue in your vaginal area to lose lubrication and elasticity, which can make intercourse painful. It may also leave you more vulnerable to urinary or vaginal infections.

Cognitive problems. A study published in Neurology found that 60% of perimenopausal women experience short-term memory loss, do not learn as well, and have a hard time concentrating. The effect is temporary, though—cognitive function improved back to previous levels during postmenopause, say researchers.

Improve daily habitsImproving your lifestyle, targeting treatments, and even turning to medication as needed can reduce symptoms dramatically. It may take a little trial and error to find what works best for you. Studies show that excess weight, stress, and smoking can increase the frequency and intensity of symptoms. Good lifestyle choices may not only help ease your transitional time, says Pinkerton, but also promote health as you age.

1. Eat less fat, more calcium. Cholesterol increases around this time, as does your risk of heart disease and osteoporosis. Reduce saturated fat in your diet, and include more calcium-rich foods—such as low-fat dairy, spinach, and white beans—to stay healthy. Also key: cutting calories. After menopause, metabolism slows, shifting hormones cause extra weight to settle in your midsection, and you lose muscle mass, so you need fewer calories to stay the same weight—50 to 100 less daily calories per decade, on average.

3. Breathe in for 5 seconds, then out for 5. Doing so for 15 minutes, twice a day, can decrease the intensity of hot flashes, report several studies. Slow, deep abdominal breathing reduces the frequency of hot flashes by 39%, research says. Scientists believe emotional stress exacerbates not only hot flashes but depression and anxiety as well. Other techniques to try: yoga and tai chi.

Target the troublemakers
Not every woman is destined to experience every symptom, and not every therapy works for every woman. Here, expert strategies for specific symptoms—try the simplest methods first for a few weeks. If you're not getting results, move on to the next.

Ease hot flashes. Take note of—and avoid—your triggers, such as heat, spicy foods, alcohol, caffeine, and smoking. Taking black cohosh supplements and undergoing acupuncture may help as well, even if for no other reason than you think it helps. Several studies show that both therapies are no better than a placebo in reducing hot flashes, but they are still significant. "For supplements in particular, taking them can decrease episodes by about 30%," says Jan Shifren, MD, director of the Vincent Menopause Program at Massachusetts General Hospital. "Whether it's a placebo effect or not, that's a lot." You can also try a combination herb like Estroven, which contains black cohosh, soy, and vitamins, or even cognitive behavioral therapy. That can give you a sense of control during a hot flash, which helps ease it by lessening the stress response, says Leslee Kagan, a clinical nurse practitioner and director of the Mind Body Program for Peri/Menopause at Massachusetts General Hospital.

Sleep better. Adopt good bedtime habits—turn off the TV, keep the bedroom cool and dark, and drink calming chamomile tea. Practicing a progressive relaxation technique may work as well: Start with your toes; tighten them for 5 seconds and release. Move your way up to your calves, thighs, abdomen, and so on, tightening each for 5 and releasing, until you reach your eyes (scrunch and relax). To ease night sweats, dress in lightweight, wicking pajamas that absorb moisture, and sleep with a fan.

Boost mood. Track your emotions and your periods to help determine if the two are connected. Some OTC products, such as Pamprin, may help ease perimenopausal irritability. Too little iron and vitamin B12 also negatively affects your moods; a supplement may help, but only if you are deficient. And studies show yoga can reduce stress.

Relieve vaginal dryness. Use a lubricant just prior to having sex; to help ease the itching and burning dryness can cause, opt for an OTC vaginal moisturizer like Replens (applied every 2 to 3 days) or vaginal estrogen creams.

Consider medical intervention
The Women's Health Initiative study in 2002 found that long-term use of hormone therapy increased risk of breast cancer and did not protect against heart disease, but scientists say that short-term use (a few years, if needed) is safe. Unless you're at high risk of breast cancer or blood clots, women in their late 40s and early 50s are usually great candidates for a low dose of hormones for the shortest time possible, says Shifren. Options to discuss with your doc for:

Heavy bleeding and cramping. Low-dose birth control pills (typically containing estrogen and progestin) can help, as well as relieve premenstrual mood swings and other symptoms. Start with a 6-month supply to get control of the bleeding. After that, it may be possible to go off, as the effects of the Pill may continue for a while, says Pinkerton. However, even low-dose pills have high levels of hormones—3 to 4 times higher than estrogen replacement therapy—so for smokers and women at an increased risk of blood clots, progesterone-only pills may be a better alternative. These are taken for 10 days before your period, so you're on fewer hormones for less time, lowering your risk of blood clots.

Intense hot flashes. Low-dose hormone therapy, or even super lowâ€“dose hormone therapy, like that of Menostar (an FDA-approved drug for preventing osteoporosis), may reduce frequency and intensity of hot flashes, says Santoro. For women at high risk of breast cancer, some doctors may prescribe other medications off-label--including clonidine (a blood pressure medication), venlafaxine (antidepressant), and gabapentin (a seizure medication), which have all been shown to lessen hot flashes.

Your top questions answered

Are there any supplements I need during perimenopause? Yes, calcium and vitamin D to help prevent bone loss. Suggested levels for D are 800 to 1,000 IU daily; for calcium, 1,000 mg if you're perimenopausal, 1,200 mg if you're postmenopausal—that's because calcium is absorbed better with estrogen, so as estrogen depletes, you need more calcium. Some doctors may also recommend vitamin B12 to relieve premenstrual mood symptoms.

If I have a hysterectomy, will I go through menopause? If both ovaries are removed, you go into an immediate "surgical" menopause, which can cause more severe symptoms. If one ovary is spared, you'll experience a typical peri/menopause, albeit about 2 years earlier than average.

Is there any way to postpone perimenopause? No, but one sure way to prevent it from starting early: Quit smoking. A Norwegian study found that women who smoke are 59% more likely to have reached menopause before age 45; for the heaviest smokers, the risk of early menopause is nearly doubled.

How long should I try a therapy? If you're trying herbs or other natural remedies, give it about 4 to 6 weeks. For hormones, you'll know within 2 weeks if they work, but it may take 6 to 8 weeks to get the full effects.

My mother began perimenopause at 42; will I? There is a genetic link, so your menstrual life will likely track that of other female relatives.

What are bioidentical hormones? They are medications that contain estrogen, progesterone, or other hormones that are chemically exact duplicates of ones our bodies produce. Some women prefer these so-called "natural" hormones, though there's no evidence that bioidenticals are better than standard hormone therapy. Some bioidenticals are made by drug companies and approved by the FDA (such as estradiol and progesterone); others are prepared at compounding pharmacies, where they are customized for each patient. These versions are not FDA approved, and they're the biggest topic of debate. Marketers claim compounded bioidenticals are safer than the commercial varieties and provide special benefits—but there's no science to support that, says Michelle Warren, MD, menopause expert at Columbia University Medical Center. In fact, some experts say custom recipes could pose more risk because individually mixed recipes have not been tested for purity and efficacy. Talk with your doctor to determine your best course of hormone treatment.